Re: select first occurrence of a table

From: Dennis Gearon <gearond(at)cvc(dot)net>
To: "Johnson, Shaunn" <SJohnson6(at)bcbsm(dot)com>
Cc: "pg-general (E-mail)" <pgsql-general(at)postgresql(dot)org>
Subject: Re: select first occurrence of a table
Date: 2003-05-02 17:58:23
Message-ID: 3EB2B1BF.8040407@cvc.net
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That's why they have something called 'surrogate keys', usually a sequence column. google for that term. I wouldn't be too hard to write a function in PL/PGSQL to fill an added key column.

Johnson, Shaunn wrote:
> Have a general SQL question:
>
> I have a table that happens to have a some
> duplicate entries in it (entire rows). I would like
> to update one row and change one thing
> about it, but it seems that I need a unique value
> to do it; otherwise, I wind up changing multiple
> rows.
>
> For example: I have a table that looks like this
>
> [snip table]
>
> Table "survey_processed_dt"
> Column | Type | Modifiers
> -------------------+---------------------------+-----------
> survid | character(8) |
> processed_id | character varying(2) |
> processed_dt | date |
>
> [/snip table]
>
> And the rows look like this:
>
>
> [snip rows]
>
> bcn=> select * from survey_processed_dt where survid = '02021000' and
> processed_id = '05';
> survid | processed_id | processed_dt
> ----------+--------------+--------------
> 02021000 | 05 | 2003-01-16
> 02021000 | 05 | 2003-01-16
> (2 rows)
>
> [/snip rows]
>
> I want to change ONE of the rows ... is there a way to
> just select the first occurrence of a row to update?
>
> Suggestions?
>
> Thanks!
>
> -X
>

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